Printing telegraph exchange system



June 20, 193.9.

F. S. KINKEAD PRINTING TELEGRAPH EXCHANGE SYSTEM 6 Sheets-Sheet l Filed March 50, 1935 /Nl/ENTOR FS. K//VKED @yg Wf/@QML/ A TTORNEV FIG? June 42o, 1939.

F. S. KINKEAD PRINTING TELEGRAPH EXCHANGE SYSTEM Filed March 30, 1935 6 Sheets-Sheet 2 /NVEN TOR E 5. K/NKE A D BWM A TTORNEY June 20, 1939. F. s. KINKEAD 2,153,431

PRINTING TELEGRAPH EXCHANGE SYSTEM FiledMarch 50, 1955 6 `Sheets-Sheet 5 R077 M4 Ac.

Si o;

/Nl/ENTOR F. 5. KIN/(EAD A TTOR/VEY June 20, 1939. F. s. KINKEAD 2,163,431

PRINTING TELEGRAPH EXCHANGE SYSTEM Filed March 50, 1935 6 Sheets-Sheet 4 ATTORNEY June 20, 1939. F. s. KINKEAD A2,163,431

PRINTING TELEGRAPH EXCHANGE SYSTEM Filed March 30, 1935 6 Sheets-Sheet 5 /NVENTOR By) MJ@ ATTORNEY.

AJune v20, 1939. F. s. KINKEAD 2,163,431

PRINTING TELEGRAPH EXCHANGE SYSTEM Filed March 50, 1935 6 Sheets-Sheet 6 /NVENTOR 5. KINK EAD 'SWA/#Mu ATTORNEY Patented June 20, 1939 UNlTED STATESV PRINTING TELEGRAPH EXCHANGE SYSTEM Fullerton S. Kinkead, Ridgefield Park, N. J., assigner to Bell Telephone Laboratories, incorporated, New York, N. Y., a corporation of New York- Application March 30, 1935, Serial No. 13,859

13 Claims.V

This invention relates to the art of telegraph communication and particularly to selective control circuits applicable principally to printing telegraph systems, whereby one or more telegraph stations associated with a given transmission circuit may be called by another substation for communication purposes.

An object of the invention is to adapt a party line transmission circuit comprising a plurality of teletypewriter stations ior operation through a central cnice switchboard.

ln Kinkead Patent 1,946,216, granted February 6, 1934, there is disclosed a system in which a plurality of printing telegraph stations are each equipped with code selecting switches and irnpulse sending devices so arranged that the operator at any station may selectively call any other station by sending a proper code consisting of successive series of impulses, each series causing 20 a temporary setting of switches and recording of the series at the called station only, whereupon the switch is released in order to receive and record the next series of impulses of the code.

The system, according to the present invention', is an adaptation of the system disclosed in Patent 1,946,216 supra, for switchboard operation whereby a switchboard operator may establish a connection directed to any station on a party line, between stations on a party line, between a station on a party line and a station on a private, or individual, line, providing such private line terminates at the switchboard, and between stations on diiierent party lines.

The invention will be more readily understood by reference to the drawings in which:

Figs. l and 2 show a party liney circuit connecting party stations lll'l, E08, |09, H0, and H2, the apparatus in party station Ili'l being shown in detail.

Fig. 3 shows a station line circuit appearing at a teletypewriter switchboard and Figs. l, 5 and 6 show an operators cord and teletypewriter circuit arranged to complete calls from the party line to other lines in the exchange.

The system is arranged so that the operator at any party station may call one or more party stations on the same line without the assistance of the switchboard operator, or may call the switchboard operator who will complete the call to another subscriber in the same exchange. The switchboard operator is also provided with facilities so that she may call one or more parties on a party line. Busy lamps are provided at all stations to indicate a busy line condition.

5 Each party on the party line is assigned an individual code. Any one of the parties on the station line circuit may be called by dialing the assigned code followed by 0, a number of stations may be called .by dialing their codes followed by l, in each case, the whole group being followed by (l, or all of the stations may be called by dialing the broadcast signal.

At each station called, the teletypewriter motors are started after receiving the O signal and an audible signal is given. The audible signal may be stopped by operating the dial and release key. In the case of the station line circuit, the signal appears as a line lamp in the teletypewriter switchboard.

Recall keys are provided so that additional stations may be called without redialing those originally connected. All of the stations are stopped by the operation of the stop key at any one station or by the transmission of the upper case H character.

If the call is to the central oflice, the operator inserts the answering plug of a cord circuit into the jack associated with the lighted line lamp, operates the teletypewriter key and obtains the desired number over the teletypewriter system in the usual manner. Completion of the call is effected by using the standard teletypewriter circuits. l lll l The operation of` the system will now be described in detail with reference to the drawings.

Individual station calls station Zine circuit Figs. l and 2 disclose a party line circuit comprising individual stations, It?, m8, HB9, Ill), andllZ, of which the apparatus in station lill is shown in detail. lt will be assumed that the operator at station Mil' desired to communicate with another station which may be reached through the teletyp-ewriter switchboard. To call the teletypewriter switchboard operator, dial and release key 228 is operated and the code of the desired station line circuit (Fig. 3), which in this case is 63, followed by the digit E) is dialed on dial 2|9. The operation of key 22E] removes the short-circuit from the pulsing contacts of dial 2|9. When dial 259 is moved off-normal, relay 2|@ operates in a path trad from ground through the left contacts of key 226, off-normal springs of dial 2W, the winding of relay 2|@ -to battery through the right-hand contact and ar-v mature of relay 252. Relay 2 lll locks in a circuit traced from ground over its innermost righthand armature and contact and winding to 'battery through the right-hand contact and armature of relay 252. Relay 2li), operates, lights busy lamp It over its middle right-hand armature and contacts.

The line relays such as relay till in station It?, and relay Sile in station line circuit 324 are all in series in a circuit traced from negative battery through the line circuits of stations |88 and |09 in series, sending mechanism 2M of station |81, receiving printer magnet 229, the contacts of break key N5, right-hand contacts of recall key 22|, the pulsing contacts of dial 2|9, outer lefthand back contact and armature of relay 202, lower windings of relay lili, line circuits of stations lill, lil and il? in series, conductor M3, inner right-hand armature and back contact of relay 3% of station line circuit 32d, upper windings of line relay silt, right-hand make-beforebreak contacts of relay ilii to positive battery. As the digit G is dialed on dial 2l@ all of the line relays such as relays lill and S follow the pulses and connect ground to their respective right-hand contacts six times. In station line circuit 32H, the release of relay 3%@ advances the switch shown as $.22 and 323 to the sixth terminal. The circuit for this function is traced from ground on the armature and right-hand contact of relay Still, left-hand make-before-break contact of relay Sli?, to battery through the winding of rotary magnet 32E. Since relay 3Q@ in following the dial pulses makes its right-hand contact six times, rotary magnet 552i will be energized six times and the wipers associated with switch banks 322 and 323 will be advanced to the sixth terminals.

The release of relay SSG also operates relay 3l l in a circuit traced from ground through the armature and right-hand contact of relay 3M, back contact and outer left-hand armature of relay @33 to battery through the winding of relay 3l l. Relay ill is of the slow to release type and does not release between dial pulses. The operation of relay Sli causes the operation of relay 3H), as soon as the switch is advanced from its normal position in a circuit traced from ground through the lower spring and make contact of oit-normal springs Sos, make-before-break contacts of relay Si?, armature and front contact of relay 3i! to battery through the winding of relay Sill. After the six pulses have been received relay 3H releases. Relay Sill, however, is of the slow to release type and does not release immediately when its operating circuit is opened by the release of relay Sli and while it is operated and relay Sil is released, a circuit is closed from ground through the lower spring and make contact of off-normal springs 369, make-before-break contacts of relay 3 l2, armature and back contact of relay 3i l, lefthand armature and front contact of relay Sill, right-hand make-before-break contacts of relay Slg, wiper and sixth terminal of bank 322, the winding of relay 307, right-hand armature and contact of relay 3l5, to battery over the back contact and outer left-hand armature of relay 3l8. Relay 3M' operates in this circuit and locks in a circuit traced from ground through its righthand armature and contact and winding, righthand armature and contact of relay 3l5 to battery through the back contact and outer lefthand armature of relay SH3. When relay siii releases, a circuit is closed from ground through the lower spring and make contact of off-normal springs 3&9, make-before-break contacts of relay 3l2, armature and back contact of relay 3 l l, leftnand armature and back contact of relay 3io, the winding of release magnet 32! to battery through the outer right-hand armature and back contact of relay 363. Release magnet 329 operates in this circuit and restores the switch to its normal position, breaking the circuit just traced when the off-normal springs 3%9 return to their normal position.

On the dialing of digit 3, relay ist releases three times operating relays 3H and Siti as before and advancing the switch to the third terminal. At the end of the train of pulses, relay Sli releases as before, and while relay Siti is still operated, a

circuit is closed from ground through the lower spring and make contact of off-normal springs 3tlg, the make-before-break contacts of relay 3 l2, armature and back Contact of relay 3l l, lefthand armature and front contact of relay Mii, right-hand make-before-break contacts of relay IS, wiper and third terminal of bank 322, front contact and left-hand armature of relay the winding of relay 392 to battery through the contact and left-hand armature of relay Slt. Relay 392 operates in this circuit and locks through its own inner right-hand armature and front contact. Relay 3W releases after an interval and operates release magnet 325i, returning the switch to normal as before.

When 0 is dialed, relay lll releases ten times and advances the switch to the tenth terminal and relays 3l l and 3 l tl are operated as in the previous selections. When relay 3l! releases, after the completion of the dial impulse train and before relay 3l@ has released, a circuit is closed from ground through the lower spring and middle contact of olf-normal springs make-beforebreak contacts of relay 3&2, armature and back contact of relay 3 l l, left armature and front con-- tact of relay 3H), right-hand make-before-break contacts of relay 3 l 9, wiper and tenth terminal of bank 322, conductors 325, 325 and 32'?, the windings of relays 3 i8 and 3l9 in parallel, outer righthand armature and back contacts of relay Elli, to battery over the back contact and the outer righthand armature of relay 3M. Relays Sill and Sia operate in the circuit just traced and lock over the inner right-hand armature and front contact ci" relay 3I9.

The operation of relay Sie transfers the operating ground for relays 3 i8 and 3 l 3 from the wiper of bank 322 to the wiper of bank 323 on a continuity basis, and as the tenth terminals ci banks 322 and 323 are strapped together, no interruption in the operating paths of relays 358 and 3l9 is caused by this transfer. The operation of relay SIS causes the operation of relay 3F36 in a circuit traced from ground over the inner right-hand armature and front contact of relay 349, left-hand armature and Contact of relay 332, the winding of relay Sil@ to battery through the back 'contact and left-hand armature of relay 365. Relay 306, operated, lights line lamp Sdi as a signal to the central oflice operator. When relay Sli! releases, release magnet 329 is operated and the switch is returned to the normal position as before.

At party station lill relay lill follows the pulses of dial 2li) as previously explained. Assuming, however, that the code of station lili' is 5S, relay 2l i will not be operated when the switch is advanced on the dialing of the digits 6 and 3 but when O is dialed the wipers will be advanced to the tenth terminals on banks 225 and 22d. The circuit for this operation is traced from ground, over the armature and the right-hand Contact of relay im, left-hand make-before-break contacts or" relay 255 to battery through the winding of rotary magnet 269. Relay M33 also operates in a circuit traced from ground over the right-hand contact of relay ll, back contact and the inner right-hand armature of relay .illii to battery through the Winding of relay Zi. Relay 2li@ is of the slow to release type and does not release between dial pulses. The operation of relay lo@ causes the operation of relay 2il2 as soon as the switch leaves its normal position in a circuit traced from ground through the lower spring and middle contact of off-normal springs itil, makeill.'

before-break contacts of relay 200, armature and iront contact of relay 203 to battery through the winding of relay 202. When the train of pulses is finished relay ll resumes its normal position, releasing relay 203. Relay 202, however, is of the slow to release type and does not release immediately when the release of relay 203 opens its operating circuit. While relay 203 is released but relay 202 is still operated a circuit is closed from i ground through the lower spring and middle centact of off-normal springs l0d,makebeiore-break contacts of relay 200, armature and back contact of relay 203, right-hand armature and front contact of relay 202, right-hand make-beforebreak contacts of relay 205, wiper and tenth terminal of bank 25, conductors 23E and 230, the windings of relays 205 and 200 in parallel, to battery over the back contact and the outer leithand armature of relay 2|2 and the back con-- tact and right-hand armature of relay 2l3. Relays 205 and 200.0perate in this circuit and lock over the front contact and innermost left-hand armature of relay 205. Relay `l now operates in a circuit traced from ground over the outermost right-hand spring and contact oi key 220,

through the winding of relay 20?, to battery over the front contact and outer left-hand armature of relay 200. Relay 20'l1 locks to ground over its front contact and outermost right-hand armature of relay 2 l0. Relay 201, operated, opens the circuit to audible signal device 223 preventing it from operating. Relays H02 and 03 operate in a circuit traced from ground over the armature and leftehand contact of relay 50i, through the winding of relay l02 and the right-hand winding of relay m3 in parallel, to battery over the front contact and inner left-hand armature of relay 205. rlhe operation of relay 200 also causes the operation of motor control relay 221 in a circuit traced from ground over the outermcst righthand armature and contact of relay 2l0, conductor 331, through the winding of relay 22?, to battery over conductors 332, and 333, the front Contact and outer left-hand armature of relay 205. Relay 22?, operated, connects battery to motor 22d causing it to rotate and condition the printer apparatus to transmit and receive printer signals.

The operator at the teletypewriter switchboard, noting the lighted line lamp 350i inserts the plug Q22 of a cord circuit, shown schematically in Figs. 4 and 5, into jack 308 associated with line lamp Btl. This closes a circuit from battery through the winding of relay 503, the upper windings of relay l, the sleeve terminals of plug 022 and jack 300, to ground through the righthand winding of relay 305. Relay 305 operates in this circuit and breaks the operating circuit of relay 300 releasing it and extinguishing lamp 3M. The operation of relay 305 also extends the line circuit to jack 303 preparing the path for teletypewriter communication which will be described later.

Relays ll and 403 also operate in the circuit traced above. Relay 404, operated, operates relay 202 by connecting ground to its winding terminal. Relay i302 operated connects the winding of relay @il to the sleeve circuit through the innermost left-hand armature and contact of relay 402 and the lower windings of relay 0.0i thus holding the relay combination comprising relays del, H02, ll03 and lill locked to the sleeve circuit. The sleeve circuit in this condition is traced from ground through the right-hand winding of relay 305, sleeve terminals of jak 308 and plug 422, to

battery through the upper winding of relay 40l and the winding of relay 403m parallel with the lower winding of relay 40| and the winding or" relay lll through the contact and innermost leithand armature of relay 402. Relay 0l also op erates relay 000 by placing ground on its leithand winding terminal and relay 402, operated, connects ground to the balancing network of the repeater relays M0 and 500.

The operator operates key 02! to associate her position circuit (Fig. 6) with the particular cord used. The operation of key 42| causes the opern ation of relay 0 I3 in a circuit traced from battery through the winding oi relay M3, make-beforebreak contacts of relay 407, the contacts of key 426 to ground through the lower winding of relay i504. rIhe circuit just traced also energizes the lower or balancing winding of relay 60A. Relay M3, operated, connects the line circuit of the cord to the teletypewriter in the operators position and causes the operation of relay Mil in a circuit traced from ground through the lower windings of relay 506, the contacts of key 22 l left-hand inner front contacts of relay M3 to battery through the winding of relay 60'3, Relay 40?, operated, transfers the operating path of relay 4I3 to ground on the inner right-hand armature of relay !llil and causes the operation of relay 40S by connecting ground over the left-hand armature and front contact of relay 40T to the winding terminal of relay 409.

The party line station operator may now com*- municate by standard teletypewriter means with either or both the switchboard operator and the operator at the called station. The teletypewriter line circuit is traced from positive battery over the normally closed left-hand contacts of relay 500, through the upper windings of relay die, outer left-hand armature and back contact of relay 550, front contact and outer left-hand armature of relay M3, through the upper windings oi relay 600, tip springs of jack SIS and plug Slg, sending mechanism S22, tip springs of plug 62E and jack 520, left-hand make-beiore-break contacts of relay 0l i, inner right-hand armature and front contact of relay M3, right-hand makebefore-break contacts of relay M2, make-beforebreak contacts of rely lill, make-before-break contacts of relay 402, ring springs of plug 022 and jack 300, outer right-hand armature and front contact of relay 305, through the upper windings of relay 304, back Contact and inner right-hand armature of relay 303, line conductor l I3, the line circuits of party stations H2, lll and H0 in series, through the lower windings of line relay l0! of party station H01, outer left-hand armature and back contacts of relay 202, front contact and outer right-hand armature of relay 20G, break contact and middle spring of key 220 which has been released, dialing being completed, the pulsing spring and contact of dial Zie, right hand contacts of key 22i, the contacts of key 2l5, through the winding of printer receiving magnet 229, sending mechanism 2M, the line circuits of party stations H09 and H08 in series to negative battery.

The further operation of the cord circuit, Figs. i and 5, and the operators telephone circuit, Fig. 6 in completing a call to another subscriber in the same exchange is substantially the same as that contained in co-pending application of G. A. Locke and li'. S. Kinkead Serial No. 459,684, filed June 7, 1930, to which reference is made for a complete description of this operation.

Stopping all stations In order to stop all stations and clear all partial selections preparatory to the next call, key 2.22 at station te? or a similar key at one of the other stations is operated. The operation of key 222 causes the operation of relay 2li by connecting ground to its winding terminal. Relay 2li locks in a circuit traced from ground through the lower spring and lowermost Contact of offnormal springs mit, bock contact and the outer right-hand, armature or" relay 2H to battery through the inner left-hand armature, contact and winding of relay 2li. Relay 2| i, operated, connects ground over its outer right-hand armature and contacts to one winding terminal of the winding of relay ZES, the other terminal being connected to battery over the contact and armature of relay 22?. Relay 2l8 operates in this circuit and locks through its inner right-hand armature and contact. The operation of relay 2l8 causes the operation of relay 26| in a circuit traced from ground through the outer right-hand armature and contact of relay 2l8, the winding oi' relay 2Q! to battery over conductor 333, front contact and outer lefthand armature of relay 2%. Relay Zll locks through its inner left-hand armature and contact and opens the operating circuit or" release magnet 283. Relays 283 and 204 now operate in a circuit traced from battery through the winding of relay @G3 in parallel with battery through the inner left-hand armature and contact of relay 296 and winding of relay Zl to ground over the inner right-hand armature and front contact of relay 2M and the armature and front contact of relay M33. Relay 202 also operates in a circuit traced from ground through the outer right-hand armature and contact of relay 2li?, Contact and inner right-hand armature of relay 2H to battery through the winding of relay 2G32. Relay 232, operated, opens the line circuit at its outer left-hand armature and contact thus releasing relay lill which opens the circuit to relays m2 and lQS releasing these relays. The release of relay HB3 opens the operating circuit of relays 2133 and 2S@ releasing the-in. Ground is now connected through the make-before-break contacts of relay HB3, the outer lefthand armature and contact or" relay 2% to battery through the winding of rotary magnet 229 operating the latter and causing the switch to take one step. When the switch has stepped off its normal contacts, off-normal springs ltlfi operate, breaking the locking circuit of relay 2 il which releases. The release of relay 2H opens the operating path of relay 2%?, releasing it. Relay 2532, released, closes the line circuit and causes the reoperation of relay lill. Relay ll operated causes the operation of relays EQ2 and M33 as before and relay lii, operated, removes ground from rotary magnet 2&9 allowing it to release and connects ground to relays 2Q@ and 2cd operating them as before. The operation of relay 2M causes the operation ol? relay ti which opens the line circuit again, releasing relay Ell and causing the release a second time of the relay chain described above and advancing the switch another terminal. This slow speed pulsing circiut opens and closes the line at a denite frequency and advances the switch one terminal for each pulse. When the signal line has been opened and closed ve consecutive times ground is connected through the lower spring and middle contacts of off-normal springs li, make-before-break contacts of relay 264, armature and back contact of relay 263, right-hand armature and front contact of relay 232, front contact and right-hand armature of relay 2l5, wiper and ifth terminal of arc 224, to battery through the winding of relay 2 l 2, operating the latter relay. Relay 2l2 locks in a circuit traced from ground over the inner left-hand armature and contact of relay 205 to battery through the innermost left-hand armature, inner left armature and contact and winding of relay 292. the windings of relays 205 and 205 releasing these relays. Relays 265 and 286, released, open the circuit to all of the operated relays except line relay H92. With all the relays released but the switch oi-normal a circuit is closed from ground through the lower spring and middle Contact of oit-normal springs make-before-brea.k contacts of relay 204, armature and back contact of relay 283, right-hand armature and back contact of relay 292, back contact and outer leitl hand armature of relay 2l!! to battery through the winding of release magnet 2%. Release magnet 2538 operates in this circuit and returns the switch to normal in which position off-normal springs Hifi release and open the operating circuit of release magnet 2&3. IThe station. circuit is now in .its original condition and in a position to receive a new call.

Relay of the station line circuit (Fig. 3) is in the slow speed pulsing circuit described above and follows the slow speed pulses. Relay 35i' is held operated on the left-hand contact and armature of relay dell while the latter relay is operated. Relay 3H is somewhat slow to release and does not release when relay 3M follows printer pulses. When the iive slow speed disconnect pulses are received, however, relay 3H is released and reoperated ve times and causes the switch wipers to be advanced to the fifth terminals on the banks 322 and 323. The operating circuit for relay 32? is traced from ground through the lefthand contacts of relay 35M, inner right-hand armature and contact of relay 3 i 8 to battery through the winding of relay Ell. The circuit for operating rotary magnet 32H of the selector is traced from ground through the back contacts of relay 3l?, outer left-hand armature and front contacts of relay 3 l 3 to battery through the winding of rotary magnet 321. The open circuits of the line and the consequent releases of relay 364 also cause the operation of relays 3H and SH2 in a circiut traced from ground through the armature and right-hand Contact of relay 304, back contact and outer left-hand armature of relay 303 to battery through the winding of relay 3H in parallel with the winding of relay SI2 and the contact and inner left-hand armature of relay SIS. As soon as the switch has taken the rst step and off-normal springs 309 have operated relay 3HE) operates in a circuit traced from ground through the lower spring and middle contact of oiT-normal springs 3529, contact and armature of relay SI2 to battery through the winding of relay 3m.

When the wipers of the switch reach the ith terminals on the banks 322 and 323 and relays Sii and 3l2 have released because relay 3M has resumed its normally operated position with its armature against its left contact, a circuit is closed from ground through the lower spring and middle Contact oi of-normal springs 309, makebefore-break contact of relay SH2, armature and back contact of relay 3l E, left-hand armature and front contact of relay dit, which because of its slow releasing characteristic remains operated for an interval after relays 3H and SI2 have Relay 2l?, operated, opens the circuit to opened its operating circuit, contact and outer right-hand armature of relay 3l9 wiper and fifth terminal of bank 323 to battery through the winding of relay SIG. Relay'SI operates in this circuit and locks in a circuit traced from ground through the inner right-hand armature and contact of relay "M9 to battery through the inner right-hand armature, contact and winding of relay Sie. When relay Sill releases ground over the lower spring and middle contact of off-normal springs SSS, through the make-before-break contacts of relay 3l2, left armature and their respective contacts of 3H and Si@ is connected to battery through the winding of release magnet 328 and the outer right-hand armature and back contact of relay 383, thereby operating release magnet 32S. Release magnet 32B, operated, returns the switch to normal and breaks the circuit through its winding when oir-normal springs 309 return to their normal position.

The operation of relay 316 opens the holding circuits of relays SIS, 3H! and S02 releasing them. Relay SIS, released, connects ground through its outer right-hand armature and contact to the tip springs of jack 368 and plugv i272 which causes supervisory lamp M15 to light in the usual manner. Relay 319 released opens the locking path of relay SI5, releasing it. When the operator noting the lighted supervisory lamp withdraws the plug from the jack relay 365 releases, restoring the station line circuit to its normal condition.

All stations may also be stopped by the transmission from any one of them of a special character, such as upper case H. When this character is received by station |01, contacts 228 on the station teletypewriter instrument are closed. The closure of these contacts causes the operation of relay 2li which when operated causes the release of all apparatus and the signaling of the operator as previously described.

The operator may stop the stations which may be operating at the time by rst operating keys @23 and 42!) and then withdrawing plug 422 from jack f'ii. The operation of key 423 causes the operation of relay M8 and the operation of key 42% causes the operation of relay M6. These relays, operated, connect positive battery to the tip of the cord circuit and cause the operation of relay M3. This circuit is traced from positive battery over the front contact and the left-hand armature of relay M6, front contact and inner right-hand armature of relay M8, front Contact and outer right-hand armature of relay M32, the tip conductors of plug 422 and jack 398, outer right-hand armature and front contact of relay 3l il, left hand armature and back contact of relay Sie; to negative battery through the right-hand winding of relay 3 I3. When plug i322 is removed from jack 3538 the operating circuit of relay 395 is opened and relay 395 released. Relay 3l3 locks in a circuit traced from ground through the lower spring and lowermost contact of oit-normal springs 3939 to battery through the left-hand armature contact and left-hand winding of relay SH3.

The operation of relay SIE causes the operation of relay 3523 in a circuit traced from ground over the outer right-hand armature and Contact of relay M3, through the winding of relay 3553 to battery through the front contact and outer left-hand armature of relay SiS. Relay locks to ground through its .inner left-hand armature. Relays 3H and SI2 now operate in a circuit ltraced fromv ground through the front contacts of relay 3l?, which is operated at this time since relay 304 is in its operated condition, front contact and outer left-hand armature of relay 363, to battery through the winding of relay 3H in parallel with the winding of relay Si? and the contact and inner left-hand of relay SiS. The operation of relay S53 also causes. the operation of relay Sill by connecting ground through the inner right-hand armature and contact of relay i3, to battery through the winding of relay 3H). With both relays 3% and Sie operated the line circuit is opened and all the line relays including line relay 35d release. The release of relay Silit opens the operating circuit of relay 3 i l which releases, closing a circuit from ground through its makebefore-break contacts, outer left-hand armature and contact of relay 3M! to battery, th ough the winding of rotary magnet 32E. Rot' y magnet 322i operates, advancesI the wipers to the terminals on the banks and operates ofi-normal springs Sile. With off-normal springs in the operated position the holding path oi relay SEB is opened and relay i i3 is released but relay Si@ is held operated in a circuit traced from ground through the lower spring and middle contacts of oli-normal springs 359, front contact and armature of relay 352 to battery through the winding of relay The release oi' relay 391i also opens the operating path of relays 3H and SL12 which release after an interval due to their slow to release characteristics. With relays 3M and 3l@ released, the operating path of relay is opened and relay Sli) released. The release o relay Si@ again closes the line circuit and causes the recuperation of line relay 3M which in turn reoperates relay 3l? over the paths previously traced. Relay 35i operated operates relays 3i! and .SI2 and breaks the circuit to rotary magnet 32E allowing it to release. The operation of relays 3M and El? cause the operation of relay Sie in a circuit traced from ground through the lower spring and middle Contact of olf-normal springs 309, iront contact and armature of relay to batt-ery through the winding of relay. Kilt. Relay Sli?, operated, opens the ,line circuit releasing relays 3M and Sill and causing the wipers to be advanced another step.

The slow speed pulsing circuit described above opens the line circuit periodically and advances the switches in all of the stations which are in the operating condition at the time. When the switch at station line circuit 31M reaches the th terminal a circuit is closed from ground through the lower spring and middle contact of orinorrnal springs back contacts of relays 3l2 and 3i i, .left-hand armature and front contact of relay till, front contact and outer right-hand armature or relay SiS, wiper and fifth terminal of bank 323 to battery through the winding of relay S95. Relay vSie operates and locks to ground through. its inner right-hand armaturey and contact and the inner right-hand armature and contacts of relay Sill. Relay l, operated, opens the operating circuits of relays 3*!8, @i9 and 392, releasing them and the release of relays 3 iii and SiS open the operating paths and release all the relays in the station line circuit l2-i with the exception of line relay EN), thus restoring station line circuit 321i to its original condition.

Recall feature Any of the stations which may oe in. operation at the time, can call vin other stations without redialing the ones already connected. To accomplish this at a station such as station lill the recall key 22| is operated. The operationv of this key starts the slow speed pulsing circuit described n eviously out does .not operate relays 2i@ and but opens the line circuit directly at th right-hand contacts of key Z2 i. vi/"hen the wipers oi the switch reach the third terminals a circuit is closed from ground through the lower spring and middle contact of off-normal springs lflfi, make-before-break contacts of relays Ei and armature and back Contact of relay Ell, righthand armature and front contact of relay front contact and right-hand armature of relay wiper and third terminal oi bank 22E., lefthand armature and contact of relay 2id to battery through the winding of relay lll. Relay 2id operates and locks in a circuit from ground through the inner left-hand armature and contact of relay 285 to lcattery through the left-hand armature contact and winding of relay 2 Re- `lay EES, operated. opens the operating paths of relays 235 and releasing them. With relays and EGG released all the relays in the circuit with the exception of relays and ll are released and the switch is returned to normal as previously described. With key 22i in its normal position the dialing circuit is again closed and any other stations may be added by dialing their codes. When the desired stations have been dialed the digit O is dialed and `as all the relays similar to relay Elli, in both the old and newly dialed stations are now operated, the relays in these stations corresponding to relays 2&5 and will operate and condition the circuits to receive printer signals as previously described. At the cperators position the operation of keys 23 and 3.2i? connects positive battery to the tip conductor or" the line, operating relay 3HE as before. ln this case, however, the plug is not removed from the jack and relays M35 and 3&2 remain operated. This circuit now functions in a similar .manner to that previously described and transmits three slow speed open circuit impulses and then conditions itself for the transmission of r1ial pulses. When the digit 0 is reoeived relays SiS and are operated and the circuit made ready to transmit printer signals.

Operator dials station To dial a station the operator inserts plug flll in jack 39d and operates position key (lili and dial key ti l l. Inserting the plug in the jack causes the operation of relays 335, dill, ist?, dell, dell and dll as previously described. The operation of position key causes relays 53, it? and to Operate as before. The operation oi dial key il il closes a circuit from ground through its righthand spring and right contact to battery through the winding of relay cl2 operating the latter relay. Relay 5i2, operated, operates relay @il by connecting ground through the inner right-hand armature and contact of relay 55E to the winding terminal or" relay Sii. Relays dit and tl i, operated, extend the line circuit to dial t l 6. The short circuit of the pulsing contacts at the lefthand spring and contact of key El? being opened by the operation of the key, the line circuit is now ready to receive dial pulses from dial The line circuit for the dialing function is traced from negative battery through station circuits Il, ESQ, lill, il, iii, H2 in s-eries, conductor S53, the line circuit of station line 326i, the ring springs of jack 3% and plug ft2?, make-beforebreak contacts of relay fm2, make-before-break contacts of relay dil, left-hand make-beforebreak contacts of relay M2, inner right-hand armature and contact of relay cl3, Contact and right-hand armature of relay 5l l, front contact and outer left-hand of relay 6 I 2, the pulsing contacts of dial tilt, outer right-hand armature and front contact of relay tid, left-hand armature and contact of relay Gi l, tip springs of jack E2G and plug 552i, sending mechanism 5H, the tip springs of plug @IS and jack till, through the upper windings of relay lli, outer left-hand armature and contact of relay M3, back contact and outer left-hand armature of relay ill, through the upper windings of relay@ l to positive battery 5cl through the normally closed contacts of relay 5M. After dialing is completed dial key @il is returned to normal, releasing relays @i2 and Si i and removing the dial from the circuit.

At the stations dialed an audible signal is given. At station im this signal is shown as buzzer 223 and is operated in a circuit traced from ground through the left-.hand armature and contact of relay 2G?, contact and inner righthand of relay Zilli, contact and left-hand armature of relay 2i@ to battery through buzzer 223. The audible signal may be silenced by the momentary operation of key 22@ which operates relay ll'l which locks and opens the circuit to the audible signal device.

Broadcast feature The circuits are arranged so that if the digit 9 is dialed the relays at every station correspondlng to relays 2l@ and 3&2 operate and lock and upon the dialing of the digit 0 the stations are connected to the line for the transmission of teletypwriter signals. For a complete description of this function reference is made to the patent to Kinkead #1,946,216.

Station to Station call A station to station call in this system is the same as that disclosed in the co-pending application of G. A. Locke et al., supra, to which reference is made for a complete description of this feature.

What is claimed is:

l. A telegraph exchange system comprising a plurality of stations, circuits extending from said stations, a switching station whereat said circuits terminate, a plurality of other stations connected in series in certain of said circuits, and means at said switching station for selectively interconnecting in response to code signals any one of said stations with any one or" the other of said stations individually, said means being further arranged, in response to a particular code signal, to interconnect any one of said stations with two or more of the other of said stations for broadcast purposes.

2. A telegraph exchange system, according to claim l, wherein means are provided for permitting any one of said other stations connected in series in said second circuit to be automatically connected to one or more of the other stations connected in the same circuit.

3. A. telegraph exchange system, according to claim l, wherein means are provided at the switching station for initiating a call to one or more stations connected in series in any one of said certain circuits.

fl. A telegraph exchange system, according to claim l, wherein means are provided at each of the stations connected in series for indicating when the line circuit of a station with which a connection is desired, is busy.

5. A telegraph exchange system, according to claim l, wherein. switches respectively provided at the stations connected in series in said certain circuits and are arranged to respond ineifectively to different incoming telegraphic codes followed by a special signal and effectively to an incoming telegraphic code individual to each of the stations connected in series provided said individual code is followed by said special signal, and wherein means are provided at each of said stations for transmitting said telegraphic codes and special signal.

6. A telegraph system, according to claim 1, wherein switches are respectively provided at the stations connected in series with each of said certain circuits and are arranged to respond ineifectively to different incoming telegraphic codes followed by a special signal and effectively to incoming telegraphic codes individual to each of the stations connected in series, provided said individual code is followed by said special signal, said switches being further arranged to respond effectively to establish for communication purposes a connection including a plurality of switches providing each individual telegraphic code of a group is followed by another special signal and the group is followed by the first mentioned special signal, and wherein means are provided at each of said stations for transmitting said telegraphic codes and special signals.

'7. A telegraph exchange system comprising a plurality of stations, a central oflice, a switchboard at said central office, a plurality of jacks at said switchboard, a plurality of line circuits respectively extending from said stations to said central office and respectively terminating at said jacks, certain of said line circuits each including two or more other stations connected in series, and link circuits at said switchboard for connecting the line circuit of any one of said stations to the line circuit of any one, or the line circuits of more than one of said stations for the transmission of a message between two or more stations, impulse sending means at said switchboard for sending code signals over said link circuit, and switching means at said switchboard, arranged when operated, to cause said code signals to operatively connect two or more of said stations connected in series in one of said line circuits, to any other of said stations through one of said link circuits, for sending broadcast messages.

8. A telegraph exchange system, according to claim 1, wherein the link circuit is comprised of manually operated cord circuits and a repeater contained therein for connecting any one of said stations to any one of said two or more stations connected to a signal line circuit.

9. A teletypewriter exchange system comprising a central oice, a multiparty line extending therefrom, a plurality of stations remote from said central office connected to said line and each provided with teletypewriter transmission and reception equipment, call responsive means at each of said stations and said central ofi-ice, a device at said central ofce and each of said remote stations, a source of signal current at said central office controlled by any one of said devices for actuating said call responsive means at said central oflice and each of said remote stations simultaneously, a circuit arrangement in each of said call responsive means for effectively signaling said central office or any one of said stations, as desired, in response to a distinctive series of signals transmitted from said any one of said devices, each of said arrangements being controlled by a series of signals different from the series of signals for controlling the other of said arrangements, teletypewriter equipment at said central office connectable to said line wherely said central office may intercommunicat-e telegraphically with said signaling station, another station and a line therefor terminating at said central oflice, teletypewriter equipment at said other station, and a cord circuit at said central oflice for extending, in response to a request from said signaling station, said first-mentioned line as a telegraphic communication circuit to said other station.

10. In a system according to claim 9, a signal device at said central office individual to said multiparty line, and means for causing said signal device to indicate busy as a result of the initiation of selective operations to select said calling means.

l1. In a telegraph system, in combination, a signal transmission circuit, a plurality of stations associated therewith, means at one or more of said stations for transmitting pulses to other stations, selective means at said other stations responsive to said pulses whereby one or more such stations may be called, means for rendering said selective means unresponsive to telegraph signals, means individual to any or all said stations whereby any said station may restore the selective means at the plurality of stations, means at one of said stations whereby said signal transmission circuit may be operatively eX- tended for intercommunication with another signal transmission circuit.

l2. In a telegraph system, in combination, a signal transmission circuit, a plurality of stations associated therewith, means at each of said stations for transmitting pulses to all said stations, selective means at each of said stations responsive to said pulses whereby one or more of said stations may be called, means for rendering said selective means unresponsive to telegraph signals, means at each of said stations whereby any of said stations may restore to normal the selective means at all said stations, another signal transmission circuit, a cord circuit at one of said stations whereby an operator thereat may extend said signal transmission circuit to said other signal transmission circuit for intercommunication between said transmission circuits, a disconnect signal at each of said stations, and means whereby any one of said stations after having been selected may energize said disconnect signal.

13. In a telegraph system, in combination, a signal transmission circuit, a plurality of stations associated therewith each equipped with a printing telegraph set, means at one or more of said stations for transmitting pulses to other of said stations, selective means at said other of said stations responsive to said pulses whereby one or more of said stations may be called and the printer set motors started thereat subsequent to said pulses, means for rendering said selective kmeans unresponsive to telegraph signals after the desired stations are called, means individual to any or all said stations whereby any station may restore to normal the selective means at all said stations, another signal transmission circuit,

and a link circuit at one of said stations whereby said signal transmission circuit may be connected to said other telegraph signal transmission circuit for telegraphic intercommunication between said signal transmission circuits.

FULLERTON S. KINKEAD. 

